Growth, invasion, metastasis, differentiation, angiogenesis and apoptosis of gastric cancer regulated by expression of PTEN encoding products

MicroRNA-214 in Health and Disease

MicroRNAs (miRNAs) are endogenously expressed, non-coding RNA molecules that mediate the post-transcriptional repression and degradation of mRNAs by targeting their 3′ untranslated region (3′-UTR). Thousands of miRNAs have been identified since their first discovery in 1993, and miR-214 was first reported to promote apoptosis in HeLa cells. Presently, miR-214 is implicated in an extensive range of conditions such as cardiovascular diseases, cancers, bone formation and cell differentiation. MiR-214 has shown pleiotropic roles in contributing to the progression of diseases such as gastric and lung cancers but may also confer cardioprotection against excessive fibrosis and oxidative damage. These contrasting functions are achieved through the diverse cast of miR-214 targets. Through silencing or overexpressing miR-214, the detrimental effects can be attenuated, and the beneficial effects promoted in order to improve health outcomes. Therefore, discovering novel miR-214 targets and understanding how miR-214 is dysregulated in human diseases may eventually lead to miRNA-based therapies. MiR-214 has also shown promise as a diagnostic biomarker in identifying breast cancer and coronary artery disease. This review provides an up-to-date discussion of miR-214 literature by describing relevant roles in health and disease, areas of disagreement, and the future direction of the field.

Metformin attenuates synergic effect of diabetes mellitus and Helicobacter pylori infection on gastric cancer cells proliferation by suppressing PTEN expression

It has been reported that CagA of Helicobacter pylori reduced PTEN expression by enhancing its promoter methylation. Furthermore, diabetes mellitus (DM) may also promote the methylation status of PTEN, a tumour suppressor gene in gastric cancer (GC). It is intriguing to explore whether DM may strengthen the tumorigenic effect of H pylori (HP) by promoting the methylation of PTEN promoter and whether the administration of metformin may reduce the risk of GC by suppressing the methylation of PTEN promoter. In this study, we enrolled 107 GC patients and grouped them as HP(-)DM(-) group, HP(+)DM(-) group and HP(+)DM(+) group. Bisulphite sequencing PCR evaluated methylation of PTEN promoter. Quantitative real-time PCR, immunohistochemistry and Western blot, immunofluorescence, flow cytometry and MTT assay were performed accordingly. DNA methylation of PTEN promoter was synergistically enhanced in HP(+)DM(+) patients, and the expression of PTEN was suppressed in HP(+)DM(+) patients. Cell apoptosis was decreased in HP(+)DM(+) group. Metformin showed an apparent effect on restoring CagA-induced elevation of PTEN promoter methylation, thus attenuating the PTEN expression. The reduced PTEN level led to increased proliferation and inhibited apoptosis of HGC-27 cells. In this study, we collected GC tumour tissues from GC patients with or without DM/HP to compare their PTEN methylation and expression while testing the effect of metformin on the methylation of PTEN promoter. In summary, our study suggested that DM could strengthen the tumorigenic effect of HP by promoting the PTEN promoter methylation, while metformin reduces GC risk by suppressing PTEN promoter methylation.

The PI3K/Akt/mTOR signaling pathway in gastric cancer; from oncogenic variations to the possibilities for pharmacologic interventions

Genetic and epigenetic alterations have been under concentrated investigations for many years in order to unearth the molecules regulating human cancer pathogenesis. However, the identification of a wide range of dysregulated genes and their protein products has raised a question regarding how the results of this large collection of alterations could converge into a formation of one malignancy. The answer may be found in the signaling cascades that regulate the survival and metabolism of the cells. Aberrancies of each participant molecule of such cascades may well result in augmented viability and unlimited proliferation of cancer cells. Among various signaling pathways, the phosphatidylinositol-3-kinase (PI3K) axis has been shown to be activated in about one-third of human cancers. One of the malignancies that is mostly affected by this axis is gastric cancer (GC), one of the most fatal cancers worldwide. In the present review, we aimed to illustrate the significance of the PI3K/Akt/mTOR axis in the pathogenesis of GC and also provided a wide perspective about the application of the inhibitors of this axis in the therapeutic strategies of this malignancy.

MicroRNA-28 promotes cell proliferation and invasion in gastric cancer via the PTEN/PI3K/AKT signalling pathway

Gastric cancer is the fourth most common malignant disease and second leading cause of cancer‑associated mortalities worldwide. Previous studies revealed aberrantly expressed microRNAs (miRNAs) in various types of human cancer; these miRNAs play important roles in tumourigenesis and tumour development. miRNAs present a considerable potential for novel therapeutic approaches for treating human cancer. Therefore, the investigation of novel miRNAs involved in gastric cancer progression provides an opportunity to improve the prognosis of patients with gastric cancer. miRNA‑28 (miR‑28) has been investigated with regards to its expression and biological functions in many types of human cancer. However, previous studies have not discussed the expression patterns, roles and associated molecular mechanisms of miR‑28 in gastric cancer. In the present study, miR‑28 expression was identified to be upregulated in gastric cancer tissues and cell lines. miR‑28 inhibition functionally inhibited cell proliferation and invasion in gastric cancer in vitro. Using bioinformatics analysis, luciferase reporter assay, reverse transcription‑quantitative polymerase chain reaction and western blot analysis, phosphatase and tensin homolog (PTEN) was mechanically identified as a direct target of miR‑28 in gastric cancer. PTEN was downregulated in gastric cancer and negatively correlated with miR‑28 levels. Inhibition of PTEN restored the biological effects of miR‑28 downregulation on the proliferation and invasion of gastric cancer cells. Notably, the downregulation of miR‑28 results in the regulation of the phosphatidylinositol 3‑kinase/protein kinase B signaling pathway in gastric cancer. These results suggested that miR‑28 may be targeted for the development of novel treatments for gastric cancer in the future.

Prognostic implications of phosphatidylinositol 3-kinase/AKT signaling pathway activation in gastric carcinomas

INTRODUCTION

Activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway plays a critical role in carcinogenesis and resistance to anticancer drugs. In this study, gastric carcinomas (GC) were investigated and statistical analyses were performed concerning the correlation between the clinicopathological features and activation of the PI3K/AKT pathway.

MATERIAL AND METHODS

Immunohistochemistry for p-AKT, p-mTOR and PTEN was performed in 239 GC and 200 non-neoplastic gastric tissues. The clinicopathological parameters were recorded from the medical charts. Statistical significance was defined by a p-value < 0.05.

RESULTS

High p-AKT expression was observed in 10% of the normal gastric tissue and in 90% of GC, and it was significantly associated with tumor size (p < 0.001), T3/T4 tumors (p < 0.001), and presence of metastases (p = 0.02). Similarly, p-mTOR positivity was found in GC cells, but not in the normal gastric mucosa, and was correlated with perineural invasion (p = 0.02) and T3/T4 tumors (p = 0.03). On the other hand, PTEN expression was weak and focal in the tumor cells, while in the normal gastric tissue this staining was strong and diffuse. Importantly, the expression of p-mTOR and PTEN was associated with overall survival.

CONCLUSIONS

The results of the present study, characterized by the loss of PTEN expression and higher expression of p-AKT and p-mTOR in the majority of tumor cells, apparently are implicated in the carcinogenesis and progression of GC. The identification of p-mTOR and PTEN expression as prognostic factors corroborates the identification and use of potential target drugs that could be more efficient for the treatment of these patients.

Downregulation of MicroRNA-147 Inhibits Cell Proliferation and Increases the Chemosensitivity of Gastric Cancer Cells to 5-Fluorouracil by Directly Targeting PTEN

Gastric cancer is the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. This study aimed to investigate the expression patterns, biological roles, and underlying mechanisms of microRNA-147 (miR-147) in gastric cancer. The present study demonstrated that miR-147 was significantly upregulated in gastric cancer tissues and cell lines. Downregulation of miR-147 decreased cell proliferation and enhanced the chemosensitivity of gastric cancer cells to 5-fluorouracil (5-FU) through the cell apoptosis pathway. In addition, phosphatase and tensin homolog (PTEN) was mechanically identified as the direct target of miR-147 in gastric cancer. PTEN knockdown reversed the effects of miR-147 downregulation on the proliferation, chemosensitivity, and 5-FU-induced apoptosis of gastric cancer cells. Moreover, miR-147 regulated the PI3K/AKT signaling pathway in gastric cancer by targeting PTEN. In conclusion, miR-147 suppressed the proliferation and enhanced the chemosensitivity of gastric cancer cells to 5-FU by promoting cell apoptosis through directly targeting PTEN and regulating the PI3K/AKT signaling pathway. This study provides important insight into the molecular mechanism that underlies the chemoresistance of gastric cancer cells. The results of this study could aid the development of a novel therapeutic strategy for gastric cancer.

Emodin inhibits HMGB1-induced tumor angiogenesis in human osteosarcoma by regulating SIRT1

The anti-cancer effects of emodin, including inhibition of proliferation, invasion, metastasis and angiogenesis, were confirmed by various previous studies. However, the specific mechanisms were not clear. In this study, we investigated emodin's anti-angiogenesis effect and focused on the mechanisms in human osteosarcoma (OS). OS cells were implanted to nude mice to form OS xenografts. Immunofluorescence assay was used to assess vWF expression in tumor tissue. MTT assay was employed to screen proper emodin concentrations unrelated with proliferation inhibition. siRNA technique was utilized to silence SIRT1 expression in OS cells. Expression levels of SIRT1 and VEGF were investigated by real-time PCR and western blotting. H4-k16Ac expression which indicated the deacetylation activity of SIRT1 was also detected by western blotting. As in results, HMGB1 treatment exacerbated OS angiogenesis both in vivo and in vitro. Emodin administration attenuated angiogenesis in both OS and HMGB1 treated OS in vivo and in vitro. After emodin treatment, the expression level and deacetylation activity of SIRT1 were dramatically enhanced. HMGB1-induced angiogenesis was more striking in SIRT1 silenced OS cells. SIRT1 silencing also impaired the anti-angiogenesis effect of emodin in OS cells.

IN CONCLUSION

SIRT expression and deacetylation activity elevation are involved in emodin's anti-angiogenesis effect in human OS.

Clinical implications of PTEN and VEGF expression status, as well as microvessel density in esophageal squamous cell carcinoma

There are limitations to the use of single biomarker levels, for example phosphate and tensin homology (PTEN) or vascular endothelial growth factor (VEGF), in the diagnosis of esophageal squamous cell carcinoma (ESCC). The present study therefore aimed to evaluate the clinical implications of combined detection of multiple biomarkers. The associations between PTEN and VEGF expression status, microvessel density (MVD), and the pathological characteristics of 50 patients with ESCC were determined using χ², analysis of variance, and t-tests. The results indicated that the PTEN-positive rate was negatively correlated with ESCC histological grade (P<0.01), depth of ESCC invasion (P<0.01) and lymph node metastasis status. Furthermore, the VEGF-positive rate was correlated with lymph node metastasis status, while MVD was correlated with the depth of ESCC invasion (P<0.01) and lymph node metastasis status (P<0.05). The PTEN-positive rate was negatively correlated with the VEGF-positive rate. A higher MVD was identified in ESCC samples than that of the normal esophageal mucosa, particularly in VEGF-positive ESCC specimens compared with those of VEGF-negative specimens, and PTEN-negative ESCC specimens compared with that of the PTEN-positive ESCC specimens. These results suggested that combined detection of PTEN and VEGF levels, as well as evaluation of MVD in patients with ESCC may provide essential information for improvements in the diagnosis and prognosis of ESCC.

Combined use of cyclophosphamide and Chalone 19-peptide in experimental breast cancer

Background

Cyclophosphamide is a potent anticancer drug, but its clinical utility is limited because of its severe side effects, in particular liver damage. Chalone 19-peptide induces apoptosis of tumor cells and inhibits tumor growth. The present study investigated the antitumor effects of a combination of cyclophosphamide and Chalone 19-peptide in experimental breast cancer.

Methods

An animal model of breast cancer was developed, consisting of an MDA-MB-231 cell line implanted in the nude mouse. Eight doses of a combination of cyclophosphamide 50 mg/kg or 100 mg/kg and Chalone 19-peptide 6.6 mg/kg were administered, and the mice were euthanized 28 days after the final drug injection. Histopathologic analysis of tumor size, metastasis, and apoptosis of cancer cells was performed. Control mice were injected intraperitoneally with either cyclophosphamide alone or the same volume of solvent.

Results

Tumor sizes in the treatment groups were smaller than in the controls. No metastasis was found in the groups treated with cyclophosphamide and Chalone 19-peptide, but lung metastasis was found in controls. Liver damage in the groups treated with cyclophosphamide was more serious than in the other groups.

Conclusion

Addition of Chalone 19-peptide can improve the ability of cyclophosphamide to inhibit tumor growth and also reduces side effects.

MiR-214 regulate gastric cancer cell proliferation, migration and invasion by targeting PTEN

Background

MicroRNAs are a class of small non-coding RNAs that play an important role in various human tumor initiation and progression by regulating gene expression negatively. The aim of this study was to investigate the effect of miR-214 on cell proliferation, migration and invasion, as well as the functional connection between miR-214 and PTEN in gastric cancer.

Methods

miR-214 and PTEN expression was determined in gastric cancer and matched normal tissues, and human gastric cancer cell lines by quantitative real-time PCR. The roles of miR-214 in cell proliferation, migration and invasion were analyzed with anti-miR-214 transfected cells. In addition, the regulation of PTEN by miR-214 was evaluated by Western blotting and luciferase reporter assays.

Results

miR-214 was noted to be highly overexpressed in gastric cancer tissues and cell lines using qRT-PCR. The expression level of miR-214 is significantly associated with clinical progression and poor prognosis according to the analysis of the clinicopathologic data. We also found that the miR-214 levels are inversely correlated with PTEN in tumor tissues. And PTEN expression level is also associated with metastasis and invasion of gastric cancer. In addition, knockdown of miR-214 could significantly inhibit proliferation, migration and invasion of gastric cancer cells. Moreover, we demonstrate that PTEN is regulated negatively by miR-214 through a miR-214 binding site within the 3’-UTR of PTEN at the posttranscriptional level in gastric cancer cells.

Conclusions

These findings indicated that miR-214 regulated the proliferation, migration and invasion by targeting PTEN post-transcriptionally in gastric cancer. It may be a novel potential therapeutic agent for gastric cancer.

mTOR inhibition by everolimus counteracts VEGF induction by sunitinib and improves anti-tumor activity against gastric cancer in vivo

VEGF receptor blockage has been reported to increase serum VEGF. We hypothesized that mTOR inhibition by everolimus counteracts VEGF induction by sunitinib resulting in an improved anti-tumor activity of sunitinib. In vitro, sunitinib in combination with everolimus did not outperform the respective monotherapies. In vivo, monotherapies reduced tumor growth by 60%, whereas the combination of sunitinib and everolimus led to an almost complete tumor growth inhibition. This superior anti-tumor activity coincided with attenuation of VEGF peaks. In conclusion mTOR inhibition by everolimus counteracts VEGF induction by sunitinib and results in significant reduction of tumor burden and long-lasting tumor growth control.

PCR-SSCP-DNA sequencing method in detecting PTEN gene mutation and its significance in human gastric cancer

AIM: To discuss the possible effect of PTEN gene mutations on occurrence and development of gastric cancer.

METHODS: Fifty-three gastric cancer specimens were selected to probe PTEN gene mutations in genome of gastric cancer and paracancerous tissues using PCR-SSCP-DNA sequencing method based on microdissection and to observe the protein expression by immunohistochemistry technique.

RESULTS: PCR-SSCP-DNA sequencing indicated that 4 kinds of mutation sites were found in 5 of 53 gastric cancer specimens. One kind of mutation was found in exons. AA-TCC mutation was located at 40bp upstream of 3’ lateral exon 7 (115946 AA-TCC). Such mutations led to terminator formation in the 297th codon of the PTEN gene. The other 3 kinds of mutation were found in introns, including a G-C point mutation at 91 bp upstream of 5’ lateral exon 5(90896 G-C), a T-G point mutation at 24 bp upstream of 5’ lateral exon 5 (90963 T-G), and a single base A mutation at 7 bp upstream of 5’ lateral exon 5 (90980 A del). The PTEN protein expression in gastric cancer and paracancerous tissues detected using immunohistochemistry technique indicated that the total positive rate of PTEN protein expression was 66% in gastric cancer tissue, which was significantly lower than that (100%) in paracancerous tissues (P < 0.005).

CONCLUSION: PTEN gene mutation and expression may play an important role in the occurrence and development of gastric cancer.

Molecular staging of gastric cancer

Gastric cancer has traditionally been staged using purely histological methods, but these methods provide little information about the biology of gastric cancer and have limited predictive power. Recent studies have shown that clinically relevant gastric cancer subtypes have distinct gene expression profiles. This approach, termed molecular staging, can lead to the discovery of novel diagnostic and prognostic biomarkers of gastric cancers. This update reviews advances in molecular staging of gastric cancer and discusses their implications for the prognosis and diagnosis of this complex disease. Technologies used in molecular staging as well as future directions for the optimization of molecular staging of gastric cancer are also discussed.

Expression and significance of hypoxia-inducible factor-1α and its regulator phosphatase and tensin homolog deleted in chromosome 10 in gastric cancer

AIM: To study the expression of hypoxia-inducible factor-1α (HIF-1α) and its regulator phosphatase and tensin homolog deleted in chromosome 10 (PTEN) in gastric cancer and their relationship with tumor angiogenesis and clinicopathologic features.

METHODS: Immunohistochemistry was performed to detect the expression of HIF-1α and its regulator PTEN in 54 cases of gastric cancer. The relationships among the expression of HIF-1α and PTEN, tumor angiogenesis and clinicopathologic features of patients were analyzed.

RESULTS: The positive expression rate of HIF-1α in gastric cancer (74.07%) was significantly higher than that in normal gastric tissue (0%, P < 0.01); the expression of HIF-1α in gastric cancer was significantly associated with TNM stage (P < 0.05), invasive depth (P < 0.01) and lymph-node metastasis (P < 0.05); the positive expression rate of PTEN in gastric cancers was low (51.9%), and reduced with increased invasive depth (38.5% vs 86.7%, P < 0.01) and clinical stage (28.6% vs 76.9%, P < 0.01), reduced histological differentiation (22.2% vs 70.6%, 63.2%, P < 0.01) and the occurrence of lymphatic (28.0% vs 72.4%, P < 0.01) and long distance metastases (16.7% vs 61.9%, P < 0.05). There was a negative correlation between the expression of HIF-1α and PTEN (r = -0.41, P < 0.05).

CONCLUSION: HIF-1α and its regulator PTEN play a very important role in the development of gastric cancer and could be useful factors in the diagnosis of gastric cancer and estimation of prognosis.

Expression of metastasis-associated gene 1, PTEN and E-cadherin in gastric carcinoma and their correlations

AIM: To investigate the expression of metastasis-associated gene 1 (MTA1), PTEN and E-cadherin in gastric carcinoma and normal gastric mucosa and their relationships with the invasion, metastasis and biological behavior of gastric carcinoma.

METHODS: Immunohistochemistry was used to examine the expression of MTA1, PTEN and E-cadherin proteins in gastric carcinoma (n = 54) and normal gastric mucosa (n = 15). The data were processed by chi-square test and the correlation was analyzed by Spearman test.

RESULTS: In comparison with those in normal gastric mucosa, the expression of MTA1 in gastric carcinoma was significantly higher (46.3% vs 6.7%, P < 0.01), and the expression of PTEN and E-cadherin in gastric carcinoma were down-regulated or even disappeared (51.9% vs 100%, 42.6% vs 100%; both P < 0.01). The expression of MTA1 and PTEN were correlated with the invasion depth (P = 0.003, P = 0.001), pathological grades (P = 0.004, P = 0.008), lymph node metastasis (P = 0.000, P = 0.001), distant metastasis (P = 0.004, P = 0.006) and clinical classification (P = 0.001, P = 0.000), and the normal expression of E-cadherin had relationship with the invasion depth (P = 0.027), pathological grades (P = 0.006), lymph node metastasis (P = 0.044), and clinical classification (P = 0.000). There was a negative correlation between the expression of MTA1 and PTEN as well as between the expression of MTA1 and E-cadherin (r = -0.518, r = -0.424; both P < 0.05), but there was a positive correlation between the expression of PTEN and E-cadherin (r = 0.53, P < 0.05).

CONCLUSION: High expression of MTA1 and low expression of PTEN and E-cadherin may be associated with the invasion and metastasis of gastric carcinoma. Combined examination of three indexes may be used to evaluate the biological behavior of gastric carcinoma.

Altered expression of transcription factor Sp1 critically impacts the angiogenic phenotype of human gastric cancer

Our recent study has shown that transcription factor Sp1 is an independent prognostic factor in gastric cancer. However, it is unclear how Sp1 impacts gastric cancer biology. Since Sp1 regulates multiple genes important to angiogenesis, we sought to evaluate the relationship between Sp1 expression and microvessel density (MVD) as well as their effects on cancer patient survival. The expression of Sp1 and status of MVD was determined using archival tissues of 86 cases of resected human gastric cancer. We found that MVD correlated highly with Sp1 expression (P < 0.001). Patients with strong Sp1 expression were 12 times more likely to have high MVD than were those with negative Sp1 expression. In univariate survival analyses, both elevated Sp1 expression (P = 0.007) and high MVD expression (P = 0.036) were associated with inferior survival. However, when Sp1 expression, MVD expression, disease stage, completeness of resection, Lauren's classification, and patient age were entered into a Cox proportional hazards model, only strong Sp1 expression (P = 0.047) and advanced stage (P < 0.01) were independently prognostic of poor survival. Furthermore, knocking down Sp1 expression significantly impaired the angiogenic potential of tumor cells in vitro and suppressed angiogenesis in vivo animal models. Therefore, we provided both clinical and experimental evidence to indicate that Sp1 might impact gastric cancer development and progression through regulating angiogenesis, a critical aspect of cancer biology.

Relationship between expression of PTEN and cyclinE and Helicobacter pylori infection in gastric cancer

AIM: To investigate the relationship between H pylori infection and PTEN, cyclinE expression in gastric cancer and adjacent mucosal tissues, and to study the possible mechanism of H pylori in gastric carcinogenesis.

METHODS: Both rapid urease and pathological test were used to examine H pylori in 59 cases of specimen. The expression of PTEN and cyclinE in gastric cancer and adjacent mucosal tissues was detected by immunohistochemical technique (SP method).

RESULTS: PTEN expression in gastric cancer tissues was significantly lower than that in the cancer adjacent tissues (50.85% vs 96.61%, P < 0.05); however, CyclinE expression in gastric cancer tissues was significantly higher than that in cancer adjacent tissues. The level of PTEN expression in well-differentiated adenocarcinoma was significantly higher than that in poorly-differentiated adenocarcinoma and mucinous carcinoma (68.4% vs 33.3%, P < 0.05 68.4% vs 37.5%, P < 0.05 respectively); however, the level of CyclinE expression in well-differentiated adenocarcinoma was significantly lower than that in poorly-differentiated adenocarcinoma and mucinous carcinoma (31.5% vs 68.8%, P < 0.05; 31.5% vs 66.7%, P < 0.05); PTEN expression in in H pylori positive group was lower than that in H pylori negative group (51.9% vs 59.4%, P > 0.05); CyclinE expression had no significant difference between H pylori positive and negative gastric cancer tissues.

CONCLUSION: Pathogenesis of gastric cancer relates to loss of suppression gene PTEN and over-expression of oncogene cyclinE, and suppression gene PTEN probably plays a role in development of gastric cancer induced by H pylori infection.

Effects of TGIF antisense oligonucleotide on proliferation and apoptosis of gastric carcinoma cells

AIM: TG interacting factor(TGIF) can inhibit both TGF-β and retinoid signaling pathways, moreover, the activation of MAPK pathway can lengthen its half life. However, its role in carcinogenesis is still unclear. Thus we attempt to investigate the effect of TGIF antisense oligodeoxynucleo-tide(ASDON) on proliferation and apoptosis of gastric carcinoma cells.

METHODS: After gastric carcinoma cells, SGC-7901, were transfected with TGIF ASDON, we analyzed the transfect efficiency by RT-PCR, its proliferation by MTT method, cell cycle and apoptosis rate via flow cytometer.

RESULTS: After transfection with TGIF ASDON, the proliferation of SGC-7901 cells was partially inhibited, and its inhibitory rate was increased to 20.4% at 72 h, whereas it had no effect on cell cycle and apoptosis of SGC-7901 cells. Followed by the treatment of TGF-β1, the growth rate of cells transfected with TGIF ASDON was distinctly reduced by 30%, and the content of G1 phase cells increased more obviously compared with the cells transfected with mutated oligonucleotides or untransfected cells.

CONCLUSION: TGIF can resist the negative regulation of TGF-β1 over proliferation and cell cycle. Most of tumor cells and interstitial cells can secrete TGF-β1, and tumor cells may resist the TGF-β1 mediated growth inhibition via TGIF, leading to the progression and even metastasis of tumor.